AstrBot/docs/en/dev/star/guides/send-message.md

# Sending Messages

## Passive Messages

Passive messages refer to the bot responding to messages reactively.

```python
@filter.command("helloworld")
async def helloworld(self, event: AstrMessageEvent):
    yield event.plain_result("Hello!")
    yield event.plain_result("你好！")

    yield event.image_result("path/to/image.jpg") # Send an image
    yield event.image_result("https://example.com/image.jpg") # Send an image from URL, must start with http or https
```

## Active Messages

Active messages refer to the bot proactively pushing messages. Some platforms may not support active message sending.

For scheduled tasks or when you don't want to send messages immediately, you can use `event.unified_msg_origin` to get a string and store it, then use `self.context.send_message(unified_msg_origin, chains)` to send messages when needed.

```python
from astrbot.api.event import MessageChain

@filter.command("helloworld")
async def helloworld(self, event: AstrMessageEvent):
    umo = event.unified_msg_origin
    message_chain = MessageChain().message("Hello!").file_image("path/to/image.jpg")
    await self.context.send_message(event.unified_msg_origin, message_chain)
```

With this feature, you can store the `unified_msg_origin` and send messages when needed.

> [!TIP]
> About unified_msg_origin.
> `unified_msg_origin` is a string that records the unique ID of a session. AstrBot uses it to identify which messaging platform and which session it belongs to. This allows messages to be sent to the correct session when using `send_message`. For more about MessageChain, see the next section.

## Rich Media Messages

AstrBot supports sending rich media messages such as images, audio, videos, etc. Use `MessageChain` to construct messages.

```python
import astrbot.api.message_components as Comp

@filter.command("helloworld")
async def helloworld(self, event: AstrMessageEvent):
    chain = [
        Comp.At(qq=event.get_sender_id()), # Mention the message sender
        Comp.Plain("Check out this image:"),
        Comp.Image.fromURL("https://example.com/image.jpg"), # Send image from URL
        Comp.Image.fromFileSystem("path/to/image.jpg"), # Send image from local file system
        Comp.Plain("This is an image.")
    ]
    yield event.chain_result(chain)
```

The above constructs a `message chain`, which will ultimately send a message containing both images and text while preserving the order.

> [!TIP]
> In the aiocqhttp message adapter, for messages of type `plain`, the `strip()` method is used during sending to remove spaces and line breaks. You can add zero-width spaces `\u200b` before and after the message to resolve this issue.

Similarly,

**File**

```py
Comp.File(file="path/to/file.txt", name="file.txt") # Not supported by some platforms
```

**Audio Record**

```py
path = "path/to/record.wav" # Currently only accepts wav format, please convert other formats yourself
Comp.Record(file=path, url=path)
```

**Video**

```py
path = "path/to/video.mp4"
Comp.Video.fromFileSystem(path=path)
Comp.Video.fromURL(url="https://example.com/video.mp4")
```

## Sending Video Messages

```python
from astrbot.api.event import filter, AstrMessageEvent

@filter.command("test")
async def test(self, event: AstrMessageEvent):
    from astrbot.api.message_components import Video
    # fromFileSystem requires the user's protocol client and bot to be on the same system.
    music = Video.fromFileSystem(
        path="test.mp4"
    )
    # More universal approach
    music = Video.fromURL(
        url="https://example.com/video.mp4"
    )
    yield event.chain_result([music])
```

![Sending video messages](https://files.astrbot.app/docs/source/images/plugin/db93a2bb-671c-4332-b8ba-9a91c35623c2.png)

## Sending Group Forward Messages

> Most platforms do not support this message type. Current support: OneBot v11

You can send group forward messages as follows.

```py
from astrbot.api.event import filter, AstrMessageEvent

@filter.command("test")
async def test(self, event: AstrMessageEvent):
    from astrbot.api.message_components import Node, Plain, Image
    node = Node(
        uin=905617992,
        name="Soulter",
        content=[
            Plain("hi"),
            Image.fromFileSystem("test.jpg")
        ]
    )
    yield event.chain_result([node])
```

![Sending group forward messages](https://files.astrbot.app/docs/source/images/plugin/image-4.png)